[v13,01/13] block: make bdev_nr_zones and disk_zone_no generic for npo2 zone size

Commit Message

Pankaj Raghav Sept. 12, 2022, 8:21 a.m. UTC

Adapt bdev_nr_zones and disk_zone_no functions so that they can
also work for non-power-of-2 zone sizes.

As the existing deployments assume that a device zone size is a power of
2 number of sectors, power-of-2 optimized calculation is used for those
devices.

There are no direct hot paths modified and the changes just
introduce one new branch per call.

Reviewed-by: Luis Chamberlain <[e-mail]>
Reviewed-by: Adam Manzanares <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Pankaj Raghav <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
---
 block/blk-zoned.c      | 13 +++++++++----
 include/linux/blkdev.h |  8 +++++++-
 2 files changed, 16 insertions(+), 5 deletions(-)

Comments

Johannes Thumshirn Sept. 12, 2022, 10:03 a.m. UTC | #1

Looks good,
Reviewed-by: Johannes Thumshirn <[e-mail]>


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Chaitanya Kulkarni Sept. 14, 2022, 5:19 p.m. UTC | #2

On 9/12/2022 1:21 AM, Pankaj Raghav wrote:
> Adapt bdev_nr_zones and disk_zone_no functions so that they can
> also work for non-power-of-2 zone sizes.
> 
> As the existing deployments assume that a device zone size is a power of
> 2 number of sectors, power-of-2 optimized calculation is used for those
> devices.
> 
> There are no direct hot paths modified and the changes just
> introduce one new branch per call.
> 
> Reviewed-by: Luis Chamberlain <[e-mail]>
> Reviewed-by: Adam Manzanares <[e-mail]>
> Reviewed-by: Hannes Reinecke <[e-mail]>
> Signed-off-by: Pankaj Raghav <[e-mail]>
> Reviewed-by: Bart Van Assche <[e-mail]>
> ---


Reviewed-by: Chaitanya Kulkarni <[e-mail]>

-ck


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Patch

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index a264621d4905..dce9c95b4bcd 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -111,17 +111,22 @@  EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock);
  * bdev_nr_zones - Get number of zones
  * @bdev:	Target device
  *
- * Return the total number of zones of a zoned block device.  For a block
- * device without zone capabilities, the number of zones is always 0.
+ * Return the total number of zones of a zoned block device, including the
+ * eventual small last zone if present. For a block device without zone
+ * capabilities, the number of zones is always 0.
  */
 unsigned int bdev_nr_zones(struct block_device *bdev)
 {
 	sector_t zone_sectors = bdev_zone_sectors(bdev);
+	sector_t capacity = bdev_nr_sectors(bdev);
 
 	if (!bdev_is_zoned(bdev))
 		return 0;
-	return (bdev_nr_sectors(bdev) + zone_sectors - 1) >>
-		ilog2(zone_sectors);
+
+	if (is_power_of_2(zone_sectors))
+		return (capacity + zone_sectors - 1) >> ilog2(zone_sectors);
+
+	return DIV_ROUND_UP_SECTOR_T(capacity, zone_sectors);
 }
 EXPORT_SYMBOL_GPL(bdev_nr_zones);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 84b13fdd34a7..ab82d1ff0cce 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -674,9 +674,15 @@  static inline unsigned int disk_nr_zones(struct gendisk *disk)
 
 static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
 {
+	sector_t zone_sectors = disk->queue->limits.chunk_sectors;
+
 	if (!blk_queue_is_zoned(disk->queue))
 		return 0;
-	return sector >> ilog2(disk->queue->limits.chunk_sectors);
+
+	if (is_power_of_2(zone_sectors))
+		return sector >> ilog2(zone_sectors);
+
+	return div64_u64(sector, zone_sectors);
 }
 
 static inline bool disk_zone_is_seq(struct gendisk *disk, sector_t sector)